If you have many Armor Stands in one area and need to select a specific one, you are able to do this via the Armor Stand Editor's targeting system.
Press the Swap Item button (F) while looking at the Armor Stand you wish to target. The target will briefly glow. If the wrong armor stand was selected, continue to target them.
The function will only work from a distance of 10 blocks away. To un-target, press the Swap Item button (F) while not looking at any Armor Stands.